Blending polymers is a simple and effective way to develop a new polymer composition possessing properties which may not be available in a single known polymer or which would require time-consuming and expensive development of an entirely new polymer. Thus, polymer blends often are used to produce a composition having some of the desired mechanical, theological, and adhesion properties found in the individual polymers used in the blend.
Fluoroplastics are used due to their properties, e.g., chemical resistance and low fuel permeation. Automotive applications, such as fuel hoses, demand lower and lower fuel permeation to minimize emissions and meet stronger environmental standards. These applications demand fluoropolymers. Thin layers of fluoropolymers often are used in combination with other materials, which provide resilience, strength, durability, and other desired properties in a composite. However, fluoropolymers are known to be difficult to bond. A variety of methods have been used to promote adhesion between fluoropolymers and non-fluoropolymers as well as between two fluoropolymers such as THV and FKM. These methods include treating the surface of one or both of the layers, using blends of two polymers such as a polyamide with a THV, mixing a polyamide and a grafted fluoropolymer having polar functionality, using tie layers, and using adhesives.